Shoe sewing machine



O. R. HAAS SHOE SEWING MACHINE Original Filed April 29, 1936 2Sheets-Sheet l (Ittornegs March 26,1940.

0. R. HAAS ,8 7

. SHOE SEWING MACHINE Original Filed April 29, 1936 2 Sheet s-Sheet 2(Ittornegs Patented Mar. 26, 1940 UNITED STATES snon SEWING MACHINE OttoR. Haas, North Beverly, Mass., assignor to United Shoe MachineryCorporation, Borough of Flemington, N. J., a corporation of New J erseyOriginal application April 29, 1936,'S erial No. 76,924. Divided andthis application April 6,

1938, Serial No. 200,413

4 Claims.

The present invention relates to sewing machines, and more particularlyto improvements in thread tensioning mechanism therefor. Theillustrative embodiment of the invention is similar 5 to that disclosedin inventors pending application Serial No. 76,924, the presentapplication being a divisionof said case.

There is frequently employed in sewing machines, particularly those ofthe lockstitch type, auxiliary thread tensioning mechanism adapted toact upon the thread between the take-up and the looper to aid in theperformance of the looping operation. I devices are, however, subject tothe disadvantage that the operation of re-threading the machine isrendered more difiic'ult and the time required for such operationthereforeincreased.

As a general rule, the thread handling mechanisms of sewing machines areenclosed, not only to protect the o-peratorfrom injury but also, in thecase of wax thread sewing machines, to provide a heat-retainingenclosurefor the'thread in its passage from the wax pot through the take-up andauxiliary tensioning devices to the looper.

In order to provide access to the enclosed devices to permitre-threading of a new thread supply, and for purposes of repair oradjustment of the parts, removable covers are employed. It has beenfound that the operator, upon completion of the threading operation orthe like, is apt to fail to close or replace the cover, with the resultthat the machine isthen operated with the thread under impropertemperature conditions and with increased risk of injury to the operatorfrom the unprotected parts.

.With the above consideration in mind it is, therefore, an object of thepresent invention to providenovel and improved thread tensioningmechanism for sewing machines, said mechanism being so constructed andarranged as to simplify substantially the operation of re-threading themachine.

Another object of the invention is the provision in a sewing machine ofthread handling mechanism of such construction and arrangement that theoperator will ofnecessity keep the cover for the thread handling devicesclosed while the machine is running.

With these objects in view, a feature of the present invention consistsin the provision in a sewing machine having stitch forming and threadhandling devices and a pivotally mounted cover for certain of saiddevices, of thread tensioning mechanism accessible for insertion of thethread therein when the cover is opened, .and operative Suchsupplementary tensioningto tension the thread only when the cover. is

closed. 1

More specifically, a feature of the invention consists in theprovisionin a sewingmachine, having stitch forming and thread handlingdevices including a thread take-up, of a cover for enclosing certain ofthe devices, said cover being pivotally mounted to permit access to thesame, and a frictional tension device acting with a yielding pressure onthe thread between the take-up and the sewing point and comprisingmembers having thread engaging surfaces, one of the members beingcarried by the cover,,whereby the device may be readily threaded whenthe, cover is open and the device rendered operative to tension thethread only upon closingthe cover.

In the drawings illustrating the preferred'embodiment of the invention,Figure 1 is a view' in front elevation of the head portion of a shoesewing machine embodying the invention, showing the cover for thetake-up mechanism in closed position, which mechanism is indicated indotted line; Figure 2 is a view in side elevation, partly in section, ofthe machine adjacent the sewing point and showing a portion of theauxiliary thread tensioning mechanism, the covers for the tension wheeland take-up mechanism being largely broken away; and Figure 3 is adetail plan view, partly in section, of the auxiliary thread tensiondevice.

The machine illustrated in the drawings is an outsole lockstitch shoesewing machine more fully illustrated and described in .inventorsapplication Ser. No. 76,924 above referred to, only so much of themachine being illustrated in the drawings as is necessary to a fullunderstanding of the invention. The work support of the machine isindicated at 4, and the presser foot at'6, while the stitch forming andthread handling devices adjacent the sewing point include a curved hookneedle 8, a curved awl II], a needle threading looper i2 and threadfinger M. A rotary loop taker is mounted above the sewing point in acircular guideway IS in the machine frame I8, and the locking threadcasein turn is "45 supported in a guideway in the loop taker. Thevarious devices are actuated by connections from a sewing cam shaft 20in the head of the machine.

The machine is provided with a take-up 22 by which the loop of theneedle thread, after being carried over the locking thread case by theloop taker, is drawn into the work to set the stitch. The take-up 22 issecured to one end of a shaft 24 rotatably mounted in the front portionof the machine frame below the sewing point. 55

The shaft is rocked by connections from the cam shaft 28 to oscillatethe take-up arm close to a stationary side flange portion 26 extendingforwardly from the machine frame and provided at its forward edge with asidewardly directed rim portion 2'5.

Each stitch is set against a uniform tension in the needle thread, thistension being provided by a tension wheel 28 rotatable in the main frameof the machine. The tension wheel is nor mally entirely enclosed by ahinged cover 38, and is provided with a brake 32, the adjustment ofwhich is effected by a thumb nut 34. From the tension wheel the needlethread passes over an idler pulley 36 and about an auxiliary take-up 38,thence over idler pulleys 39 and to the pulley 62 on the main take-uplever 22. The thread, prior to passing over the tension wheel 28, isdrawn through the usual wax pot, not shown.

To retain the thread in properly heated condition in its passage overthe auxiliary and main take-ups 38 and 22 respectively, and to shieldthe operator from the rapidly oscillating take-up lever, there isprovided a cover 44 having a for wardly offset portion generallyparallel to and adapted to cooperate with the rim portion 27 of theprojecting flange 25 to form an enclosure for the take-up mechanism. Thecover is mounted on the machine frame by means of a horizontal hinge 4-6at its lower edge to permit the cover to be swung outwardly anddownwardly away from the take-up 22 to render the needle handlingdevices accessible for re-threading and for repair and adjustment. Ahandle 68 on the cover enables the same to be opened and closedconveniently.

To assist in carrying out the looping operation by insuring that theneedle thread will be stretched between the looper l4 and the threadfinger It so as to engage and be retained in the needle hook, there isprovided an auxiliary frictional tension device acting upon the needlethread between the take-up 22 and the looper Hi. In order that there-threading operation may not be rendered more difficult by theaddition of the said auxiliary tensioning device the mechanism thereofis mounted partly on the take-up cover M and partly on the flangeportion 26 of the casing so that the device is opened automatically whenthe take-up cover is opened.

The thread tensioning mechanism comprises a plate 552 slidably mountedin the upper part of the flange 26 of the take-up casing, the platebeing so positioned relative to the lead of the thread between thepulley 42 on the take-up lever 22 and the looper !2 that the thread isdrawn to the sewing point across the face of the plate, as shown inFigure 2. A headed pin 52 (see Figure 3), secured at one end to theplate 50 and passing loosely through the side of the flange serves tohold the plate in position while permitting movement of the platelaterally. The plate is urged away from the flange and toward theportion if: of the cover M by small springs E l received in recesses inthe flange 26.

The forwardly offset portion of the take-up cover M is formed along itsupper edge with a suitable surface 56 substantially parallel to andarranged to cooperate with the plate 57.! of the tension device. Whenthe cover 44 is swung open to expose the take-up mechanism, the surface56 is moved forwardly out of alignment with the plate and the threadbetween the take-up lever 22 and the looper !2 passes loosely across thesurface of the plate 50, as in Figure 2. When the cover is swung intothe closed position shown in Figure 3, a bevelled surface 58 on thecover forces the thread to the right, the plate 50 yielding to permitthe thread to enter between the parallel friction surfaces of the coverand plate.

By this arrangement of take-up cover and thread tensioning mechanism,not only is the operation of re-threading the machine substantiallysimplified, but also it is insured that the operator will close thecover before starting the machine, since the thread tens-ion necessaryto the proper operation of the machine is obtained only with the coverin closed position.

While the invention has been illustrated and described as embodied in alockstitch shoe sewing machine of particular construction andarrangement, the invention is not limited thereto in its application,and may be. embodied in sewing machines of other types. limited to theparticular form and arrangement shown and described, but embraces otherconstructions and arrangements within the scope of the appended claims.

Having thus described the invention, what is n claimed is:

1. A sewing machine having, in combination, stitch forming and threadhandling devices, a cover for enclosing certain of said devices, the

cover being movable away from closed position to permit access to thedevices, and frictional thread tension mechanism comprising membershaving thread engaging surfaces arranged to act with yielding pressureon the thread between certain of the thread handling devices when thecover is in closed position, movement of the cover away from closedposition causing the thread engaging surfaces to separate to permitinsertion of the thread therebetween.

2. A sewing machine having, in combination, stitch forming devicescomprising a hook needle and a take-up, a pivotally mounted cover toenclose or permit easy access to certain of the stitch forming devices,and a frictional tension device acting with a yielding pressiu'e on thethread bethe point of operation of the needle, and comprising membershaving parallel thread engaging surfaces disposed at right angles to thetake-up shaft, one of said surfaces being carried by said cover.

4. A sewing machine having, in combination, stitch forming devicescomprising a hook needle and a take-up, a shaft on which the take-up ismounted, a stationary guard at one side of the path of movement of thetake-up, a removable cover arranged when in position to surround theother side of the take-up path, and a frictional tension device actingwith a yielding pressure on the thread between the take-up and the pointof operation of the needle and comprising n1c1nbers having threadengaging surfaces, carried by said guard and said cover, respectively.

OTTO R. 'rIAAS.

Nor is the invention

